A good thermometer and a handy hot water tap and you can keep the processes pretty close. The tanks are pretty good at holding temperature for the short times the developer will be in them.
Ari - these blasted little chips, for all the PITA they are, are sealed. Nothing can get inside (at least not photo chemistry - anything that would melt that plastic would destroy your CPP). Perhaps a short as the liquid does appear to have run between the components.
I'd be more worried about the components in the far-left of your red circle. It certainly looks as though the magic smoke has been let out of those with all the apparent discoloration.
(a couple hours later) Looked at the catalog of the electronics supply outfit I normally use (Mouser Electronics, Texas, USA) - The IC chip is a voltage comparator and they sell them for $1.23US singly.
The blue critter appears to be a tantalum capacitor - from your description it is a 6.3wvdc and 10%tolerance of value but can't tell anything else from the numbers. About $1.25US
The yellow guy may be a resistor. If there's voltage sensing going on (the IC voltage comparator), this may be to drop voltage to an acceptable voltage level running the IC with the blue capacitor in parallel acting as a ripple filter.
Your friend at Tech may be your best way out - as the other fellow said, he can trace the circuit and check the in and out voltage of the resistor (if that's what it is) and figure the value that's supposed to be there rather easily.
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Last edited by Frank Szabo; 07-20-2008 at 03:23 PM.
A good thermometer and a handy hot water tap and you can keep the processes pretty close. The tanks are pretty good at holding temperature for the short times the developer will be in them.
Yeah, temperature control is not a big problem, especially since my times are usually under 6 minutes and I have an air conditioner right above the Jobo. Lowering the temperature of the water is a -lot- more of a hassle than warming it up and keeping it there.
The thing is that if I need to send the machine or the circuit back to Germany, that means that for a considerable amount of time I would have to do without it, old skool dev-ing!
Quote:
Originally Posted by Frank Szabo
Ari - these blasted little chips, for all the PITA they are, are sealed. Nothing can get inside (at least not photo chemistry - anything that would melt that plastic would destroy your CPP). Perhaps a short as the liquid does appear to have run between the components.
I'd be more worried about the components in the far-left of your red circle. It certainly looks as though the magic smoke has been let out of those with all the apparent discoloration.
Yes, you are probably right Frank.
I have already contacted a friend who works in the Institute of Technological Research of Crete (kinda like our own MIT, one of the top in Europe) and told him about my problem and he will take it to one of the technicians there to take a look at it.
I was wondering, if one can replace the chips, if needed, by ordering replacements from somewhere. I am sure an electronic technician can replace those bulbous components which seem much more common.
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Yeah, temperature control is not a big problem, especially since my times are usually under 6 minutes and I have an air conditioner right above the Jobo. Lowering the temperature of the water is a -lot- more of a hassle than warming it up and keeping it there.
The thing is that if I need to send the machine or the circuit back to Germany, that means that for a considerable amount of time I would have to do without it, old skool dev-ing!
Yes, you are probably right Frank.
I have already contacted a friend who works in the Institute of Technological Research of Crete (kinda like our own MIT, one of the top in Europe) and told him about my problem and he will take it to one of the technicians there to take a look at it.
I was wondering, if one can replace the chips, if needed, by ordering replacements from somewhere. I am sure an electronic technician can replace those bulbous components which seem much more common.
I can't quite read the marking from your photograph, but it looks like a 74 series logic chip - look for a number starting something like '74LS...' to identify it.
In any event, if it is 74 series logic, it will cost literally pence to replace; although I'd concur that the chip itself is unlikely to be damaged, it's more likely to be a pin corrosion problem. In any event, if you can find someone with basic soldering skills and a decent parts tray, they should be able to eliminate the possibility that chip is a problem in a matter of minutes.
(Even if it's not 74 series, it is 99% certain to be a standard part not made of unobtainium, and should be reasonably easy to replace.)
The 'bulbous component' looks like a tantalum capacitor; given its location it's probably a decoupling or smoothing capacitor used to eliminate ripple from the power supply to the chips; again, the component will be pence to replace (and in fact there's a good chance the board will work fine without it, although you'd not exactly recommend that as good practice .)
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Allright then, we are getting somewhere!
Tim, if you are interested, the writing on the parts is:
Chip: 23AY35M, SN74LS85N
Yellow Capacitor: K1K
Blue Capacitor: +10, +6.3V
I did a test and plugged it in, being careful for the heating element not to touch anything. I twisted the first knob where 3 should be (for 30 degrees) and noticed two things:
- The heating element doesn't seem to get warmer
- There is a component in the board that looks to have some sort of enclosed in plastic switch of two parts that come together or separate with a click when the temperature knob is twisted in certain parts. I am not sure what it does exactly though, nor did I notice any difference in the heating when it was closed or opened.
The thing is... what if that's not the problem?
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Sounds like the control circuit is working, thats a relay you are looking at. Seems the power to the heater or the heater itself is at fault.
So, the chip and capacitors are ok then?
What should I look for?
The rest of the circuit looks fine (for a layman).
Funny, but I even thought that maybe the first knob doesn't point to 30 or 20 degrees which means that the thermometer (which is working fine along with the LED display) wouldn't let the heating element work as the ambient temperature is above twenty degrees celcius.
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Final cut- let your friend at the Institute check it out with a meter. That person should be pretty familiar with circuit tracing and should be able to pinpoint where the power disappears.
If the relay is clicking on and off when you twist the temperature control either side of ambient room temperature then the heat sensing and control circuit is working. It is more likely that the heating element itself is broken. Someone with a multimeter should be able to tell you if it has gone open circuit.
I have a CPP-2 in my shed which is just gathering dust and I don't expect I will ever use (I think it's a CPP-2, I will check when I get home). If you can determine what part is broken you are welcome to have that part from mine and/or any other circuit boards and parts for spares.
Another option for temperature control is to get something like this: http://www.screwfix.com/prods/61083/...Cylinder-Stat# from a plumbing supply store and fit it to the outside of the tank. Use it to control the heating element via a relay or if your element is broken, perhaps a submersible heater possibly from an aquarium supplies company. Be sure to get one that goes down to 20 degrees c though. As they are intended for domestic hot water clamped to the outside of the hot water cylinder, some of them start at 40.
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